The invention relates to rechargeable batteries, particularly of the zinc-air cell type. More specifically, the invention relates to a battery having an anode comprising a replaceable stationary zinc particle bed with recirculating electrolyte.
Zinc-air primary (non-rechargeable) cells are known, such as Sauer, et al. U.S. Pat. No. 4,115,626. Secondary (rechargeable) zinc-air cells are known as well. For example in Ross, U.S. Pat. No. 4,842,963, a battery is disclosed using a porous foam electrode containing deposited zinc. Electrolyte is recirculated through the electrode using an external pump and electrolyte reservoir.
Other approaches to a rechargeable zinc-air battery are disclosed in a series of Doniat, et al. U.S Pat. Nos. 3,887,400, 3,981,747, and 4,126,733. In these systems, a bed of zinc particles is fluidized by the passage of electrolyte upwardly through the bed under the influence of a pump. The patent discloses various techniques for electrochemically regenerating the zinc in situ.
A problem with each of the foregoing rechargeable batteries relates to pumping electrolyte in external recirculation loops. The pumps consume substantial energy and add considerable weight to the battery. This is a particular disadvantage for electric vehicles which would use a large numbers of such cells.
It would be highly advantageous to provide a rechargeable battery which can be rapidly recharged at home or at a service station and yet which would provide excellent performance characteristics. Moreover, it would be desirable to provide such a battery which eliminates external electrolyte reservoirs and circulator loops powered by energy-consuming pumps.